U.S. patent application number 12/972030 was filed with the patent office on 2011-06-30 for stage control device, stage control method, stage control program, and microscope.
This patent application is currently assigned to SONY CORPORATION. Invention is credited to Yu Hirono, Koichiro Kishima, Ryu Narusawa, Fumiyasu Suzuki, Takashi Yamamoto.
Application Number | 20110157349 12/972030 |
Document ID | / |
Family ID | 44173878 |
Filed Date | 2011-06-30 |
United States Patent
Application |
20110157349 |
Kind Code |
A1 |
Yamamoto; Takashi ; et
al. |
June 30, 2011 |
STAGE CONTROL DEVICE, STAGE CONTROL METHOD, STAGE CONTROL PROGRAM,
AND MICROSCOPE
Abstract
A stage control device is provided and includes: an obtaining
section obtaining a set of images as different visual points in all
or a part of a sample set as a photographing object; a distance
calculating section calculating a distance between each pixel of
one image to be set as a reference in the set of images and a
relative pixel in the other image; a tilt angle calculating section
calculating a tilt angle of the sample using the distance
calculated by the distance calculating section; and an adjusting
section adjusting a tilt angle of a stage surface on which the
sample is disposed so as to minimize a tilt within an angle of view
of a photographed picture on a basis of the tilt angle of the
sample.
Inventors: |
Yamamoto; Takashi; (Tokyo,
JP) ; Kishima; Koichiro; (Kanagawa, JP) ;
Narusawa; Ryu; (Kanagawa, JP) ; Hirono; Yu;
(Tokyo, JP) ; Suzuki; Fumiyasu; (Saitama,
JP) |
Assignee: |
SONY CORPORATION
Tokyo
JP
|
Family ID: |
44173878 |
Appl. No.: |
12/972030 |
Filed: |
December 17, 2010 |
Current U.S.
Class: |
348/79 ; 348/373;
348/E5.024; 348/E7.085 |
Current CPC
Class: |
G02B 21/36 20130101;
G02B 27/0075 20130101; G02B 21/14 20130101; G01Q 30/20 20130101;
G02B 21/24 20130101; G02B 21/26 20130101; G02B 21/006 20130101 |
Class at
Publication: |
348/79 ; 348/373;
348/E07.085; 348/E05.024 |
International
Class: |
H04N 7/18 20060101
H04N007/18; H04N 5/225 20060101 H04N005/225 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 25, 2009 |
JP |
P2009-295382 |
Jun 28, 2010 |
JP |
P2010-146745 |
Claims
1. A stage control device comprising: obtaining means for obtaining
a set of images as different visual points in all or a part of a
sample set as a photographing object; distance calculating means
for calculating a distance between each pixel of one image to be
set as a reference in said set of images and a relative pixel in
the other image; tilt angle calculating means for calculating a
tilt angle of said sample using the distance calculated by said
distance calculating means; and adjusting means for adjusting a
tilt angle of a stage surface on which said sample is disposed to
minimize a tilt within an angle of view of a photographed picture
on a basis of the tilt angle of said sample.
2. The stage control device according to claim 1, wherein when an
amount of adjustment of the tilt angle of the stage surface on
which said sample is disposed is equal to or larger than a
threshold value, said adjusting means readjusts the tilt angle.
3. The stage control device according to claim 1, wherein said tilt
angle calculating means calculates both a tilt angle in an X-Z
direction of said sample and a tilt angle in a Y-Z direction of
said sample, and said adjusting means adjusts a tilt angle in a
short side direction of the stage surface on which said sample is
disposed so as to minimize the tilt within the angle of view of the
photographed picture on a basis of the tilt angle in said X-Z
direction, and adjusts a tilt angle in a long side direction of the
stage surface on which said sample is disposed so as to minimize
the tilt within the angle of view of the photographed picture on a
basis of the tilt angle in said Y-Z direction.
4. The stage control device according to claim 3, wherein said
adjusting means starts to adjust the tilt angle in the short side
direction of the stage surface on which said sample is disposed
after completing adjusting the tilt angle in the long side
direction of the stage surface.
5. A stage control method comprising: obtaining a set of images as
different visual points in all or a part of a sample set as a
photographing object; calculating a distance between each pixel of
one image to be set as a reference in said set of images and a
relative pixel in the other image; calculating a tilt angle of said
sample using the distance calculated in said distance calculating
step; and adjusting a tilt angle of a stage surface on which said
sample is disposed so as to minimize a tilt within an angle of view
of a photographed picture on a basis of the tilt angle of said
sample.
6. A stage control computer program product stored on a
computer-readable medium including executable instructions that
when executed by a processor perform steps for: obtaining a set of
images as different visual points in all or a part of a sample set
as a photographing object; calculating a distance between each
pixel of one image to be set as a reference in said set of images
and a relative pixel in the other image; calculating a tilt angle
of said sample using the calculated distance; and adjusting a tilt
angle of a stage surface on which said sample is disposed so as to
minimize a tilt within an angle of view of a photographed picture
on a basis of the tilt angle of said sample.
7. A microscope comprising: a stage having a surface on which a
sample is disposed, the stage being movable in a direction parallel
to the surface and a direction orthogonal to the surface, and the
stage being capable of changing a tilt angle of the surface; an
objective lens for forming an image of a part of the sample
disposed on said surface; an optical system for forming a set of
images as different visual points using the image formed in said
objective lens; distance calculating means for calculating a
distance between each pixel of one image to be set as a reference
in the set of images formed by said optical system and a relative
pixel in the other image; tilt angle calculating means for
calculating a tilt angle of said sample using the distance
calculated by said distance calculating means; and adjusting means
for adjusting a tilt angle of the stage surface on which said
sample is disposed so as to minimize a tilt within an angle of view
of a photographed picture on a basis of the tilt angle of said
sample.
8. A stage control device comprising: an obtaining section
obtaining a set of images as different visual points in all or a
part of a sample set as a photographing object; a distance
calculating section calculating a distance between each pixel of
one image to be set as a reference in said set of images and a
relative pixel in the other image; a tilt angle calculating section
calculating a tilt angle of said sample using the distance
calculated by said distance calculating section; and an adjusting
section adjusting a tilt angle of a stage surface on which said
sample is disposed so as to minimize a tilt within an angle of view
of a photographed picture on a basis of the tilt angle of said
sample.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] The present application claims priority to Japanese Patent
Application JP 2009-295382 filed on Dec. 25, 2009 and Japanese
Patent Application JP 2010-146745 filed on Jun. 28, 2010, the
entire contents of which are hereby incorporated by reference.
BACKGROUND
[0002] The present disclosure relates to a stage control device, a
stage control method, a stage control program, and a microscope,
and is suitable for observing a tissue section, for example.
[0003] In pathological examination, a tissue section is fixed to a
glass slide, subjected to a staining process and an enclosure
process, and prepared as a preparation. In general, when the
preparation is stored for a long period of time, the visibility of
the preparation under a microscope is degraded due to degradation
of the living body sample, color fading, and the like. In addition,
the preparation may be microscopically examined in facilities other
than facilities such for example as a hospital that prepared the
preparation, and the preparation is generally sent and received by
mail, which requires a certain time.
[0004] In view of such an actual situation and the like, a device
storing a living body sample as image data is proposed (see
Japanese Patent Laid-Open No. 2009-175334, for example). This
device uses a focusing technique for focusing on a living body
sample on the basis of the contrast of a picked-up image.
SUMMARY
[0005] A living body sample has a thickness. When images of the
entire region in a direction of thickness (direction of depth) of
the living body sample are to be picked up, the number of picked-up
images depends on a depth of field of an objective lens.
[0006] For example, when the thickness of the living body sample in
a preparation is 100 [.mu.m], and the depth of field of the
objective lens is 1 [.mu.m], at least 100 picked-up images need to
be obtained.
[0007] The number of picked-up images is reduced as the depth of
field is increased. However, this is not desirable because the
picked-up images are increased in degree of blurring and thus
degraded in quality.
[0008] The present embodiment has been made in view of the above
points. It is desirable to propose a stage control device, a stage
control method, a stage control program, and a microscope that can
improve efficiency of obtainment of images of a sample without
changing the depth of field.
[0009] According to an embodiment, there is provided a stage
control device including: obtaining means for obtaining a set of
images as different visual points in all or a part of a sample set
as a photographing object; distance calculating means for
calculating a distance between each pixel of one image to be set as
a reference in the set of images and a relative pixel in the other
image; tilt angle calculating means for calculating a tilt angle of
the sample using the distance calculated by the distance
calculating means; and adjusting means for adjusting a tilt angle
of a stage surface on which the sample is disposed so as to
minimize a tilt within an angle of view of a photographed picture
on a basis of the tilt angle of the sample.
[0010] According to an embodiment, there is provided a stage
control method including: an obtaining step of obtaining a set of
images as different visual points in all or a part of a sample set
as a photographing object; a distance calculating step of
calculating a distance between each pixel of one image to be set as
a reference in the set of images and a relative pixel in the other
image; a tilt angle calculating step of calculating a tilt angle of
the sample using the distance calculated in the distance
calculating step; and an adjusting step of adjusting a tilt angle
of a stage surface on which the sample is disposed so as to
minimize a tilt within an angle of view of a photographed picture
on a basis of the tilt angle of the sample.
[0011] According to an embodiment, there is provided a stage
control program for making a computer perform the steps of:
obtaining a set of images as different visual points in all or a
part of a sample set as a photographing object; calculating a
distance between each pixel of one image to be set as a reference
in the set of images and a relative pixel in the other image;
calculating a tilt angle of the sample using the calculated
distance; and adjusting a tilt angle of a stage surface on which
the sample is disposed so as to minimize a tilt within an angle of
view of a photographed picture on a basis of the tilt angle of the
sample.
[0012] In addition, according to an embodiment, there is provided a
microscope including: a stage having a surface on which a sample is
disposed, the stage being movable in a direction parallel to the
surface and a direction orthogonal to the surface, and the stage
being capable of changing a tilt angle of the surface; an objective
lens for forming an image of a part of the sample disposed on the
surface; an optical system for forming a set of images as different
visual points using the image formed in the objective lens;
distance calculating means for calculating a distance between each
pixel of one image to be set as a reference in the set of images
formed by the optical system and a relative pixel in the other
image; tilt angle calculating means for calculating a tilt angle of
the sample using the distance calculated by the distance
calculating means; and adjusting means for adjusting a tilt angle
of the stage surface on which the sample is disposed so as to
minimize a tilt within an angle of view of a photographed picture
on a basis of the tilt angle of the sample.
[0013] The embodiments can maintain the number of photographs in a
direction of thickness (direction of depth) of a sample set as a
photographing object at substantially the same level even when the
sample is in a tilted state or a preparation itself to which the
sample is fixed is in a tilted state.
[0014] Therefore, the embodiments can greatly reduce the number of
photographs in the direction of thickness of the sample as compared
with a case of photographing the sample remaining in a tilted
state. In addition to this, the embodiments can greatly reduce a
load in a process of searching for an in-focus position as compared
with a case of searching for the in-focus position with the sample
remaining in a tilted state.
[0015] Thus, a stage control device, a stage control method, a
stage control program, and a microscope that can improve efficiency
of obtainment of images of a sample without changing a depth of
field are each realized.
[0016] Additional features and advantages are described herein, and
will be apparent from the following Detailed Description and the
figures.
BRIEF DESCRIPTION OF THE FIGURES
[0017] FIG. 1 is a schematic diagram showing a constitution of a
microscope;
[0018] FIG. 2 is a photograph showing a photographing object image
and phase difference images of a tissue section;
[0019] FIG. 3 is a schematic diagram showing an example of driving
constitution of a preparation stage;
[0020] FIGS. 4A and 4B are schematic diagrams showing a tilted
state of a preparation disposition surface;
[0021] FIG. 5 is a schematic diagram showing a functional
configuration of a stage control section;
[0022] FIG. 6 is a schematic diagram showing a depression and
projection state of a tissue section;
[0023] FIG. 7 is a schematic diagram showing a parallax of each
pixel of one image with respect to another image of phase
difference images;
[0024] FIG. 8 is a schematic diagram of assistance in explaining a
straight line most closely approximating the parallax (depression
and projection distribution) of each pixel in an X-Z direction;
[0025] FIGS. 9A and 9B are schematic diagrams of assistance in
explaining adjustment of tilts in a long side direction and a short
side direction on the preparation disposition surface;
[0026] FIG. 10 is a flowchart of a tilt angle adjusting process
procedure;
[0027] FIGS. 11A and 11B are schematic diagrams of assistance in
explaining limitation of parts where phase difference images are
obtained;
[0028] FIG. 12 is a schematic diagram of assistance in explaining
limitation of parts where phase difference images are obtained;
[0029] FIG. 13 is a schematic diagram of assistance in explaining a
parameter (1) related to a condition for determining whether to
adjust a tilt angle or not; and
[0030] FIG. 14 is a schematic diagram of assistance in explaining a
parameter (2) related to a condition for determining whether to
adjust a tilt angle or not.
DETAILED DESCRIPTION
[0031] Embodiments will hereinafter be described. Incidentally,
description will be made in the following order.
[0032] <1. Embodiment>
[0033] [1-1. Constitution of Microscope]
[0034] [1-2. Preparation Stage Driving Constitution]
[0035] [1-3. Functional Constitution of Stage Driving Control
Section]
[0036] [1-4. Tilt Angle Adjusting Process Procedure]
[0037] [1-5. Effects and Others]
[0038] <2. Other Embodiments>
1. Embodiment
1-1. Constitution of Microscope
[0039] FIG. 1 shows a constitution of a microscope 1 according to
an embodiment. The microscope 1 has a stage 11 on which a
preparation PRT can be disposed (which stage will hereinafter be
referred to also as a preparation stage).
[0040] The preparation PRT is prepared by fixing a section of a
tissue such as a connective tissue of blood or the like, an
epithelial tissue, both tissues or the like to a glass slide SG by
a predetermined fixing method. The tissue section is stained as
required. Staining includes not only staining referred to as
general staining typified by HE (hematoxylin and eosin) staining,
Giemsa staining, Papanicolaou staining or the like but also
staining referred to as special staining such as FISH (Fluorescence
In-Situ Hybridization), an enzyme antibody technique or the
like.
[0041] A light source 12 is disposed on an opposite surface side of
the preparation stage 11 from a surface on which the preparation
PRT is disposed (which surface will be referred to also as a
preparation disposition surface). The light source 12 can select
and apply light for illuminating a tissue section that has
undergone general staining (which light will hereinafter be
referred to also as bright field illumination light) or light for
illuminating a tissue section that has undergone special staining
(which light will hereinafter be referred to also as dark field
illumination light). However, a light source 12 capable of applying
bright field illumination light or dark field illumination light
may be applied.
[0042] A condenser lens 13 having a normal of a reference position
on the preparation disposition surface as an optical axis is
disposed between the preparation stage 11 and the light source
12.
[0043] An objective lens 14 having the normal of the reference
position on the preparation disposition surface as an optical axis
is disposed on the side of the preparation disposition surface of
the preparation stage 11. This objective lens 14 is selected from a
plurality of objective lenses of different magnifications by a lens
selecting mechanism through an electric operation or a manual
operation.
[0044] A half mirror 15 is disposed in the rear of the objective
lens 14. The half mirror 15 divides light incident from the
objective lens 14 into transmitted light and reflected light. An
image pickup element 16 having a surface on which a subject image
of the objective lens 14 is formed as an image pickup surface is
disposed in the rear of a transmission side of the half mirror
15.
[0045] On the other hand, a field lens 17 is disposed in the rear
of a reflection side of the half mirror 15. The field lens 17
relays the subject image of the objective lens 14 which image is
projected onto the reflection side of the half mirror 15 to the
rear (intended image forming surface). The field lens 17 condenses
the subject light reflected by the half mirror 15, and therefore
suppresses a decrease in brightness on the periphery of a field of
view.
[0046] A diaphragm mask 18 is disposed in the rear of the field
lens 17. The diaphragm mask 18 has a pair of apertures 18A and 18B
at symmetric positions of a surface orthogonal to the optical axis
of the field lens 17 with the optical axis of the field lens 17 as
a boundary. The diaphragm mask 18 divides a subject luminous flux
incident from the field lens 17 by the apertures 18A and 18B. The
divided luminous fluxes intersect each other at the image forming
surface of the subject luminous flux, and positional relation
between the luminous fluxes in front of the image forming surface
and positional relation between the luminous fluxes in the rear of
the image forming surface are interchanged.
[0047] Separator lenses 19A and 19B are disposed in the rear of the
pair of apertures 18A and 18B, respectively. The separator lenses
19A and 19B subject the divided luminous fluxes divided by the
corresponding apertures 18A and 18B to tilt image formation
(shift), and thereby form two subject images of different visual
points (which images will hereinafter be referred to also as phase
difference images) on the intended image forming surface relayed by
the field lens 17.
[0048] Incidentally, when the separator lenses 19A and 19B are
affected by vignetting (shading) of the field lens 17, part of the
divided luminous fluxes are lost. The separator lenses 19A and 19B
are therefore arranged close to the central side of the field lens
17 so as not to be affected by the vignetting. In addition, the
depth of field of the separator lenses 19A and 19B is set wider
than the depth of field of the objective lens 14. The depth of
field of the separator lenses 19A and 19B is set by a process of
setting an aperture adjusting section for changing the size of the
apertures 18A and 18B in the diaphragm mask 18.
[0049] An image pickup element 20 is disposed in the rear of the
separator lenses 19A and 19B. This image pickup element 20 is not a
line sensor but an area sensor. That is, the image pickup element
20 is disposed with a surface on which the phase difference images
of the subject appearing in the objective lens 14 are formed as an
image pickup surface.
[0050] A stage driving control section 31, an illumination control
section 32, and image pickup control sections 33 and 34 are
provided as a control system in the microscope 1. These control
sections are a computer including a CPU (Central Processing Unit),
a ROM (Read Only Memory), a RAM (Random Access Memory) serving as a
work memory for the CPU, arithmetic circuitry and the like.
[0051] The stage driving control section 31 moves (scans) the
preparation stage 11 in a direction parallel to the preparation
disposition surface so that the tissue section TS of the
preparation PRT is allocated to a condensed light part where light
is condensed by the condenser lens 13.
[0052] The stage driving control section 31 also moves the
preparation stage 11 in a direction orthogonal to the preparation
disposition surface (that is, a direction of thickness of the
tissue section) so that the objective lens 14 is focused on a part
of the tissue section TS allocated to the condensed light part.
[0053] The illumination control section 32 sets a parameter
corresponding to a mode in which to obtain a bright field image
(which mode will hereinafter be referred to also as a bright field
mode) or a mode in which to obtain a dark field image (which mode
will hereinafter be referred to also as a dark field mode) in the
light source 12, and makes illumination light applied from the
light source 12. This parameter is for example the intensity of the
illumination light and a selection of a kind of light source.
[0054] Incidentally, the illumination light in the bright field
mode is generally visible light. On the other hand, the
illumination light in the dark field mode is light including a
wavelength for exciting a fluorescent marker used in special
staining. In addition, a background part with respect to the
fluorescent marker is cut out in the dark field mode.
[0055] When the illumination light is applied from the light source
12, the illumination light is condensed to a reference position of
the preparation disposition surface on the preparation stage 11 by
the condenser lens 13. An image of the condensed light part where
the light is condensed by the condenser lens 13 in the tissue
section TS in the preparation PRT is magnified and formed on the
image forming surface of the objective lens 14, and the magnified
image is formed as a subject image on the image pickup surface of
the image pickup element 16. In addition, the subject image
reflected by the half mirror 15 is formed as phase difference
images on the image pickup surface of the image pickup element 20
by the separator lenses 19A and 19B.
[0056] Pictures of the bright field image formed on the image
pickup element 16 and the phase difference images formed on the
image pickup element 20 are shown in FIG. 2. As is clear from FIG.
2, the subject image appearing in the objective lens 14 is formed
on the image pickup surface of the image pickup element 16, and is
meanwhile formed as phase difference images on the image pickup
surface of the image pickup element 20 by the separator lenses 19A
and 19B.
[0057] The image pickup control section 33 sets a parameter
corresponding to the bright field mode or the dark field mode in
the image pickup element 16, and obtains the data of the subject
image formed on the image pickup surface of the image pickup
element 16. This parameter is for example timing of starting
exposure and timing of ending the exposure.
[0058] The image pickup control section 34 sets a parameter
corresponding to the bright field mode or the dark field mode in
the image pickup element 20, and obtains the data of the phase
difference images formed on the image pickup surface of the image
pickup element 20. This parameter is for example timing of starting
exposure and timing of ending the exposure.
[0059] The stage driving control section 31, the illumination
control section 32, and the image pickup control sections 33 and 34
are connected with a control section 30 for performing integrated
control of the whole of the microscope 1 as a control system at a
higher level than the control sections 31 to 34 (which control
section 30 will hereinafter be referred to also as an integrated
control section) via a data communication channel.
[0060] This integrated control section 30 is a computer including a
CPU, a ROM, a RAM, an arithmetic circuit, an interface, and the
like. The interface is detachably connected with a peripheral
device such as an operating input section, a display section, a
storage medium or the like.
[0061] The integrated control section 30 waits for a start
instruction to start the bright field mode or the dark field mode.
When receiving the start instruction, the integrated control
section 30 issues a command to start control in the mode
corresponding to the start instruction to the stage driving control
section 31, the illumination control section 32, the image pickup
control section 33, and the image pickup control section 34.
[0062] Then, each time the allocation of a part of the tissue
section TS disposed in the preparation PRT to the condensed light
part where light is condensed by the condenser lens 13 is changed,
the integrated control section 30 obtains the data of a magnified
image in the part of the tissue section TS, which data is output
from the image pickup element 16, and stores the data on a storage
medium.
[0063] In addition, the integrated control section 30 waits for a
display instruction. When receiving the display instruction, the
integrated control section 30 reads data corresponding to a
magnified image specified by the display instruction from the
storage medium, and supplies the data to a source that sent the
display instruction.
[0064] Thus, the microscope 1 stores the tissue section TS in the
preparation PRT as images in a microscopically examined state, and
can thereby store information on the tissue section TS for a long
period of time without degrading states of fixture, staining and
the like as compared with a case of storing the preparation PRT
itself.
1-2. Preparation Stage Driving Constitution
[0065] The preparation stage 11 in the microscope 1 is configured
so as to be able to move in a direction orthogonal to a direction
parallel to the preparation disposition surface and change the tilt
angle of the preparation disposition surface.
[0066] The driving constitution of the preparation stage 11 is
illustrated in FIG. 3. The preparation stage 11 illustrated in FIG.
3 is supported at three points by bar-shaped supporting members 51,
52, and 53 disposed on an opposite surface (back surface) from the
preparation disposition surface.
[0067] One end of the supporting member 51 is in point contact with
a position PO1 on a diagonal line of the back surface of the
preparation stage 11 and in the vicinity of a corner set as a
reference. Another end of the supporting member 51 is fixed to a
stage 54 serving as a supporting base (which stage will hereinafter
be referred to also as a base stage).
[0068] One end of the supporting member 52 is in point contact with
a position PO2 where a diagonal line of the back surface of the
preparation stage 11 intersects an imaginary line that passes
through the point in contact with one end of the supporting member
51 and which is parallel to a long side of the preparation stage
11. Another end of the supporting member 52 is coupled to a
mechanism 55 for extending and contracting the supporting member 52
in a direction orthogonal to the preparation disposition surface
(which mechanism will hereinafter be referred to also as a
supporting member extending and contracting mechanism) according to
a direction of rotation of a shaft rotating with an actuator AT1 as
a driving source.
[0069] One end of the supporting member 53 is in point contact with
a position PO3 where the diagonal line of the back surface of the
preparation stage 11 intersects an imaginary line that passes
through the point in contact with one end of the supporting member
51 and which is parallel to a short side of the preparation stage
11. Another end of the supporting member 53 is coupled to a
mechanism (supporting member extending and contracting mechanism)
56 for extending and contracting the supporting member 53 in the
direction orthogonal to the preparation disposition surface
according to a direction of rotation of a shaft rotating with an
actuator AT2 as a driving source.
[0070] The length of the supporting members 52 and 53 (length of a
straight line connecting one end to the other end at a shortest
distance) when the preparation disposition surface is in a
horizontal state is set as an initial length in the supporting
member extending and contracting mechanisms 55 and 56.
[0071] In addition, the present embodiment employs springs 57A,
57B, and 57C coupled to the preparation stage 11 and the base stage
54 as a force imparting mechanism for imparting a force acting in a
direction of bringing the preparation stage 11 and the base stage
54 closer to each other.
[0072] When the supporting member 52 is extended or contracted with
the initial length as a reference, as shown in FIG. 4A, the
preparation disposition surface tilts to a short side direction
(Y-direction) side with the supporting members 51 and 53 as
supporting points. The angle of the tilt is increased as the length
of the supporting member 52 extended or contracted by the
supporting member extending and contracting mechanism 55 deviates
more from the initial length.
[0073] When the supporting member 53 is extended or contracted with
the initial length as a reference, as shown in FIG. 4B, the
preparation disposition surface tilts to a long side direction
(X-direction) side with the supporting members 51 and 52 as
supporting points. The angle of the tilt is increased as the length
of the supporting member 53 extended or contracted by the
supporting member extending and contracting mechanism 56 deviates
more from the initial length. Incidentally, in the tilt state shown
in FIGS. 4A and 4B, the supporting member 52 is contracted with the
initial length as a reference.
[0074] The preparation stage 11 shown in FIG. 3 can thus change the
tilt angle of the preparation disposition surface.
[0075] In the present embodiment, at the position PO2 in point
contact with one end of the supporting member 52, a groove for
guiding the corresponding contact end in the short side direction
(Y-direction) is formed, and at the position PO3 in point contact
with one end of the supporting member 53, a groove for guiding the
corresponding contact end in the long side direction (X-direction)
is formed.
[0076] Thus, a shift in supporting position of the supporting
members 51, 52, and 53 with respect to the preparation stage 11 is
prevented. As a result, the tilt angle of the preparation
disposition surface can be adjusted stably and accurately.
[0077] On the other hand, a base stage moving mechanism 58 is
coupled to a predetermined position of the base stage 54. The base
stage moving mechanism 58 has an X-axis and a Y-axis orthogonal to
each other in a horizontal plane and a Z-axis in normal relation to
the horizontal plane. The base stage moving mechanism 58 moves the
base stage 54 in directions (the X-direction and the Y-direction)
parallel to the preparation disposition surface and a direction
(Z-direction) orthogonal to the preparation disposition surface
separately according to directions of rotation of the axes.
[0078] Thus, the preparation stage 11 is moved in the same
direction as a direction of movement of the base stage 54 moved by
the base stage moving mechanism 58 via the supporting members 51,
52, and 53.
[0079] The preparation stage 11 shown in FIG. 3 is thus movable in
the directions parallel to the preparation disposition surface and
the direction orthogonal to the preparation disposition
surface.
[0080] Incidentally, a holding section 59 for holding the
preparation PRT in place is provided on the preparation disposition
surface of the preparation stage 11 shown in FIG. 3, and a hole for
guiding light applied from the light source 12 to the preparation
PRT held by the holding section 59 is provided in the preparation
stage 11.
[0081] A mode of arrangement of the light source 12 and the
condenser lens 13 (FIG. 1) with respect to the preparation stage 11
shown in FIG. 3 is a matter of design, and various modes can be
selected. For example, there is a mode in which both of the light
source 12 and the condenser lens 13 are disposed between the
preparation stage 11 and the base stage 54 or below the base stage
54. However, when the light source 12 is disposed below the base
stage 54, the base stage 54 needs to have a hole for guiding the
light applied from the light source 12.
[0082] As another example, there is a mode in which a reflecting
mirror is disposed between the preparation stage 11 and the base
stage 54, and the light source 12 and the condenser lens 13 are
disposed in other than a space between the stages. In this mode,
the light applied from the light source 12 is guided from a side of
the base stage 54 to the preparation PRT via the reflecting
mirror.
1-3. Functional Constitution of Stage Control Section
[0083] Next, FIG. 5 shows a functional configuration of the stage
driving control section 31 (FIG. 1) for controlling the supporting
member extending and contracting mechanisms 55 and 56 and the base
stage moving mechanism 58. As shown in FIG. 5, the stage driving
control section 31 functions as a base stage control section 61, a
phase difference image obtaining section 62, a parallax calculating
section 63, a section tilt angle calculating section 64, and a
stage tilt angle adjusting section 65 according to a tilt angle
adjusting process program.
[0084] The base stage control section 61 moves the base stage 54 in
the X-direction or the Y-direction as appropriate by controlling
the base stage moving mechanism 58, and thereby allocates the
preparation PRT or the tissue section TS on the preparation to the
condensed light part where light is condensed by the condenser lens
13.
[0085] Each time a part of the tissue section TS on the preparation
which part is allocated to the condensed light part where light is
condensed by the condenser lens 13 is changed, the phase difference
image obtaining section 62 obtains the data of phase difference
images in the corresponding section part from the image pickup
element 20.
[0086] The parallax calculating section 63 calculates a distance
between each pixel of one image to be set as a standard (which
image will hereinafter be referred to also as a standard image) of
the phase difference images and a relative pixel of the other image
(which image will hereinafter be referred to also as a reference
image) (which distance will hereinafter be referred to also as a
parallax).
[0087] Specifically, each pixel in the standard image is selected
as a pixel as an object of interest (which pixel will hereinafter
be referred to as a pixel of interest) in order. Then, each time a
pixel of interest is selected, a pixel relative to the pixel of
interest is detected from the reference image, and a parallax
(distance) between the pixel and the pixel of interest is
calculated.
[0088] Incidentally, as a method for detecting the relative pixel,
a method is for example applied which detects a block having a
highest degree of similarity to pixel values in a block of m
pixels.times.n pixels with the pixel of interest as a center from
the reference image by a normalized correlation method, for
example, and sets the center of the detected block as the relative
pixel.
[0089] The smaller the parallax is, the nearer to the rear the
focal point of the objective lens 14 is positioned, whereas the
greater the relative distance is, the nearer to the front the focal
point is positioned. Thus, as shown in FIG. 6, the parallax of each
pixel in the phase difference images corresponds to information
indicating a depression and projection state of a photographing
range (region appearing on the image forming surface of the
objective lens 14) AR in the tissue section in the preparation
PRT.
[0090] The relation of the parallax (distance) between the position
of each pixel in the standard image and the pixel relative to the
pixel in the standard image is shown as a graph in FIG. 7. A light
part in the graph of FIG. 7 represents a top side, and a dark part
in the graph of FIG. 7 represents an underside. FIG. 7 shows that
the depression and projection state of parts of the tissue section
projected on the image forming surface of the objective lens 14 is
reflected. Incidentally, an end of a part of the tissue section
shown as phase difference images in FIG. 7 is turned up.
[0091] When the parallax calculating section 63 has calculated
parallaxes in the phase difference images of all parts assigned to
the tissue section TS, the section tilt angle calculating section
64 calculates the tilt angles of the tissue section TS using the
parallaxes.
[0092] Specifically, for example, as shown in FIG. 8, a straight
line SL most closely approximating the parallax distribution of
each pixel in the X-Z direction is detected for each column Y0, Y1,
. . . , Yn in the Y-direction by a method of least squares, for
example. Then, a plane passing through the most of the straight
lines of the respective Y-columns is determined by averaging the
angles of the respective straight lines with respect to a
horizontal plane, for example. That is, the tissue section TS is
approximated to a plane closest to the depression and projection
state as viewed from the X-Z direction. An angle formed between the
plane and the horizontal plane is calculated as a tilt angle of the
tissue section TS (which tilt angle will hereinafter be referred to
also as an X-Z direction tilt angle).
[0093] Similarly, a straight line most closely approximating the
parallax distribution of each pixel in the Y-Z direction is
detected for each column in the X-direction. A plane passing
through the most of the straight lines of the respective X-columns
is detected. That is, the tissue section TS is approximated to a
plane having a slope closest to the depression and projection state
as viewed from the Y-Z direction. A slope angle formed between the
plane and the horizontal plane and a direction thereof are
calculated as a tilt angle of the tissue section TS (which tilt
angle will hereinafter be referred to also as a Y-Z direction tilt
angle).
[0094] When the plane approximating section 64 has calculated the
X-Z direction tilt angle of the tissue section TS, the stage tilt
angle adjusting section 65 adjusts the tilt angle of the
preparation disposition surface so that the X-Z direction tilt
angle with respect to the horizontal plane is 0.degree..
[0095] Specifically, an amount of extension or contraction (that
is, an amount of height adjustment and a direction thereof) of the
supporting member 52 corresponding to the X-Z direction tilt angle
is determined. Then, a direction of rotation and an amount of
rotation of the actuator AT1 in the supporting member extending and
contracting mechanism 55, the direction of rotation and the amount
of rotation of the actuator AT1 corresponding to the amount of
extension or contraction of the supporting member 52, is set in the
supporting member extending and contracting mechanism 55.
[0096] As a result, as shown in FIG. 9A, the tilt angle on the
short side direction (Y-direction) side of the preparation
disposition surface is adjusted with the contact points PO1 and PO3
of the supporting members 51 and 53 as supporting points, so that
the tissue section TS as viewed from the X-Z direction is in a
substantially horizontal state even though the tissue section TS
has the depression and projection state. Even if the tissue section
TS is tilted on the slide, the tissue section TS is set in a
substantially horizontal state.
[0097] When the plane approximating section 64 has calculated the
Y-Z direction tilt angle of the tissue section TS, on the other
hand, the stage tilt angle adjusting section 65 adjusts the tilt
angle of the preparation disposition surface so that the Y-Z
direction tilt angle with respect to the horizontal plane is
0.degree..
[0098] Specifically, as in the case of the X-Z direction plane, an
amount of extension or contraction of the supporting member 53
corresponding to the Y-Z direction tilt angle is determined. Then,
a direction of rotation and an amount of rotation of the actuator
AT2 in the supporting member extending and contracting mechanism
56, the direction of rotation and the amount of rotation of the
actuator AT2 corresponding to the amount of extension or
contraction of the supporting member 53, is set in the supporting
member extending and contracting mechanism 56.
[0099] As a result, as shown in FIG. 9B, the tilt angle on the long
side direction (X-direction) side of the preparation disposition
surface is adjusted with the contact points PO1 and PO2 of the
supporting members 51 and 52 as supporting points, so that the
tissue section TS as viewed from the Y-Z direction is in a
substantially horizontal state even though the tissue section TS
has the depression and projection state.
[0100] Incidentally, the stage tilt angle adjusting section 65
adjusts the tilt angle on the short side direction (Y-direction)
side of the preparation disposition surface after adjusting the
tilt angle on the long side direction (X-direction) of the
preparation disposition surface.
[0101] A tilt angle on a direction side whose adjustment was
completed first may be changed by a minute amount when a tilt angle
on a direction side as an object of subsequent adjustment is being
adjusted. Thus, as compared with a case of adjusting the tilt angle
on the short side direction (Y-direction) side first, adjusting the
tilt angle on the long side direction (X-direction) side first can
reduce an amount of change in the tilt angle whose adjustment was
completed first due to the adjustment of the object of subsequent
adjustment.
1-4. Tilt Angle Adjusting Process Procedure
[0102] A tilt angle adjusting process procedure in the stage
driving control section 31 will next be described with reference to
a flowchart of FIG. 10.
[0103] When a command to start control is issued to the stage
driving control section 31, the stage driving control section 31
starts the tilt angle adjusting process procedure, and proceeds to
first step SP1. The stage driving control section 31 in first step
SP1 starts scanning the preparation stage 11 supported on the base
stage 54 via the supporting members 51 to 53 by controlling the
base stage moving mechanism 58. The stage driving control section
31 then proceeds to second step SP2.
[0104] The stage driving control section 31 in second step SP2
obtains phase difference images of all parts of the tissue section
TS allocated to the photographing range AR (FIG. 5). The stage
driving control section 31 then proceeds to third step SP3.
[0105] The stage driving control section 31 in third step SP3
calculates a parallax in the phase difference image of each part.
The stage driving control section 31 then proceeds to fourth step
SP4.
[0106] The stage driving control section 31 in fourth step SP4
calculates the X-Z direction tilt angle and the Y-Z direction tilt
angle of the tissue section TS with respect to the horizontal
plane. The stage driving control section 31 then proceeds to fifth
step SP5.
[0107] The stage driving control section 31 in fifth step SP5
adjusts the tilt angle in the long side direction (X-direction) of
the preparation disposition surface so that the Y-Z direction tilt
angle of the tissue section TS with respect to the horizontal plane
is 0.degree. (FIG. 8B). The stage driving control section 31 then
proceeds to sixth step SP6.
[0108] The stage driving control section 31 in sixth step SP6
adjusts the tilt angle in the short side direction (Y-direction) of
the preparation disposition surface so that the X-Z direction tilt
angle of the tissue section TS with respect to the horizontal plane
is 0.degree. (FIG. 8A). The stage driving control section 31 then
proceeds to seventh step SP7.
[0109] The stage driving control section 31 in seventh step SP7
determines whether amounts of adjustment of the tilt angles in the
long side direction (X-direction) and the short side direction
(Y-direction) of the preparation disposition surface are less than
a threshold value. When the amounts of adjustment of the tilt
angles in the long side direction (X-direction) and the short side
direction (Y-direction) of the preparation disposition surface are
not less than the threshold value, the stage driving control
section 31 returns to fifth step SP5 to repeat the process in fifth
step SP5 and sixth step SP6.
[0110] When the amounts of adjustment of the tilt angles in the
long side direction (X-direction) and the short side direction
(Y-direction) are less than the threshold value, on the other hand,
the stage driving control section 31 ends the tilt angle adjusting
process procedure.
[0111] Thus, when the amounts of adjustment of the tilt angles in
the long side direction (X-direction) and the short side direction
(Y-direction) of the preparation disposition surface are not less
than the threshold value, the stage driving control section 31
readjusts the tilt angles until the amounts of adjustment of the
tilt angles in the long side direction (X-direction) and the short
side direction (Y-direction) of the preparation disposition surface
become less than the threshold value. Hence, even when a tilt angle
on a direction side whose adjustment was completed first is changed
while a tilt angle on a direction side as an object of subsequent
adjustment is being adjusted, the stage driving control section 31
can finely adjust the change to a certain amount.
1-5. Effects and Others
[0112] In the above constitution, the stage driving control section
31 obtains phase difference images of all parts of the tissue
section TS allocated to the photographing range AR (FIG. 5), and
calculates a parallax from each phase difference image (FIG. 6).
Then, the stage driving control section 31 calculates the tilt
angle of the tissue section TS with respect to the horizontal plane
using the parallax calculated from each phase difference image, and
adjusts the tilt angle of the preparation disposition surface such
that the tilt angle of the tissue section TS is 0.degree. with
respect to the horizontal plane.
[0113] Thus, even when the tissue section TS is tilted on the
slide, or even when the preparation PRT itself is tilted, the stage
driving control section 31 can maintain the number of photographs
taken in a direction of thickness of the tissue section TS as a
photographing object at substantially the same level. As a result,
the number of photographs taken in the direction of depth of the
tissue section TS can be greatly reduced as compared with a case of
photographing the tissue section TS that remains tilted.
[0114] In general, when the preparation PRT is disposed on the
preparation stage 11, foreign matter such as dust or the like is
interposed between the preparation stage 11 and the preparation
PRT. FIGS. 11A and 11B show that the number of photographs is
increased in a case where dust is interposed (FIG. 11A) as compared
with a case where the dust is not interposed (FIG. 11B).
[0115] For example, when the objective lens 14 has a magnification
of 20.times. and the image pickup surface of the image pickup
element 16 has dimensions of 4 cm.times.6 cm, the photographing
region AR (FIG. 5) on the preparation PRT has dimensions of about 2
mm.times.3 mm. The slide in the preparation PRT generally has
dimensions of 25 mm.times.75 mm.
[0116] When a dust of 100 .mu.m is interposed in the vicinity of
one short side of the preparation PRT under this condition, a slope
of about 4 .mu.m is added each time the preparation PRT is moved by
3 mm in the X-direction. In this case, when the depth of field of
the objective lens 14 is 1 .mu.m, the number of photographs is
increased by four per unit of 3 mm. It should thus be understood
that the number of photographs is greatly increased with the mere
interposition of a dust of 100 .mu.m.
[0117] Thus being able to reduce the number of photographs greatly
by maintaining the number of photographs in the direction of
thickness of the tissue section TS to be photographed at
substantially the same level is very useful from a viewpoint of
improving efficiency of obtainment of tissue section images.
[0118] In addition, a load in a process of searching for an
in-focus position can be reduced by maintaining the number of
photographs in the direction of thickness of the tissue section TS
to be photographed at substantially the same level. Thus, the
efficiency of obtainment of tissue section images can be further
improved.
[0119] According to the above constitution, the microscope 1
capable of improving the efficiency of obtainment of tissue section
images can be realized by making it possible to reduce the number
of photographs greatly and reduce a load in a process of searching
for an in-focus position.
2. Other Embodiments
[0120] In the foregoing embodiment, a tissue section TS is applied
as a living body (organism) sample. However, living body samples
are not limited to this embodiment. For example, smears,
chromosomes and the like are applicable as living body samples. In
addition, samples other than living body (organism) samples, such
for example as semiconductor devices, may also be applied.
[0121] In addition, in the foregoing embodiment, phase difference
images of the tissue section TS are obtained from the image pickup
element 20. However, a source from which phase difference images of
the tissue section TS are obtained is not limited to the image
pickup element 20. For example, phase difference images of the
tissue section TS may be obtained from a storage medium connected
to the integrated control section 30. In addition, phase difference
images of the tissue section TS may be obtained from the outside of
the microscope 1 via a wire or wireless communication medium such
as a local area network, the Internet or the like.
[0122] In addition, in the foregoing embodiment, the directions of
changing the tilt angles of the preparation disposition surface of
the preparation stage 11 are the same as the X-direction and the
Y-direction as in-plane moving directions of the preparation
disposition surface. However, the directions of changing the tilt
angles are not limited to the same directions as the moving
directions of the preparation disposition surface, but may be
different directions from the moving directions of the preparation
disposition surface.
[0123] Incidentally, from a viewpoint of reducing a processing load
in a process of calculating the tilt angles of the preparation
disposition surface and the like, it is more desirable that the
directions of changing the tilt angles be the same as the moving
directions of the preparation disposition surface than a case where
the directions of changing the tilt angles are different from the
moving directions of the preparation disposition surface.
[0124] In addition, in the foregoing embodiments, the number of
directions in which to change the tilt angles of the preparation
disposition surface of the preparation stage 11 is two, that is,
the X-direction and the Y-direction as in-plane moving directions
of the preparation disposition surface. However, the number of
directions in which to change the tilt angles is not limited to
two.
[0125] For example, one of the X-direction and the Y-direction as
in-plane moving directions of the preparation disposition surface
may be set as direction in which to change the tilt angles of the
preparation disposition surface of the preparation stage 11.
Incidentally, it is preferable that the number of directions in
which to change the tilt angles be one from a viewpoint of reducing
a processing load in a process of calculating the tilt angles of
the preparation disposition surface and the like. However, it is
preferable that the number of directions in which to change the
tilt angles be two from a viewpoint of improving the accuracy of
adjustment of the tilt angles.
[0126] In addition, in the foregoing embodiment, the X-direction
and the Y-direction as in-plane moving directions of the
preparation disposition surface are in orthogonal relation to each
other. However, the orthogonal relation of the in-plane moving
directions is not an essential condition.
[0127] In addition, in the foregoing embodiment, the supporting
members 51, 52, and 53 are disposed in a state of being orthogonal
to the preparation disposition surface. However, the supporting
members 51, 52, and 53 may be disposed in a state of being tilted
with respect to the preparation disposition surface.
[0128] In addition, in the foregoing embodiment, the supporting
members 51, 52, and 53 each have a bar shape. However, the shape of
the supporting members 51, 52, and 53 is not limited to a bar
shape. In addition, while the supporting members 51, 52, and 53
generally have the same shape, the supporting members 51, 52, and
53 may have respective shapes different from each other.
[0129] Incidentally, when the supporting members 51, 52, and 53
having a large cross-sectional area are used, it suffices to form a
taper at one end of the supporting members 51, 52, and 53 from a
tip to another terminal thereof. Then, the preparation stage 11 can
be supported at three points more stably.
[0130] In addition, in the foregoing embodiment, the positions of
the contact points of the supporting members 51, 52, and 53 are the
positions PO1, PO2, and PO3 in the vicinity of stage corners.
However, the positions of the contact points are not limited to the
positions PO1, PO2, and PO3. Various positions other than the
arrangement positions such that each contact point is on a straight
line can be set as the contact points of the supporting members 51,
52, and 53.
[0131] In addition, in the foregoing embodiment, a constitution in
which the tilt angles of the preparation disposition surface of the
preparation stage 11 can be changed in both of the X-direction and
the Y-direction as moving directions of the preparation disposition
surface independently is illustrated in FIG. 3 as a constitution in
which the tilt angles of the preparation disposition surface of the
preparation stage 11 can be changed. However, the constitution
shown in FIG. 3 is a mere example.
[0132] For example, a constitution may be adopted in which the
preparation stage 11 is provided to a shaft center in the
Z-direction in the stage driving mechanism via a ball joint and the
ball joint is driven to change the tilt angles of the preparation
disposition surface. In short, various constitutions in which the
tilt angles of the preparation disposition surface can be changed
are widely applicable.
[0133] In addition, in the foregoing embodiment, phase difference
images of all parts of the tissue section TS allocated to the
photographing range AR (FIG. 5) are obtained. However, parts of the
tissue section TS to be obtained as phase difference images are not
limited to all the parts of the tissue section TS.
[0134] For example, as shown in FIG. 12, phase difference images of
two regions ARx1 and ARx2 as ends in the long side direction of the
tissue section TS and two regions ARy1 and ARy2 as ends in the
short side direction of the tissue section TS may be obtained. In
addition, a region having a barycenter of the tissue section TS may
be added to these parts. In short, it suffices for the regions to
be a part of the tissue section TS.
[0135] However, when one of the X-direction and the Y-direction as
in-plane moving directions of the preparation disposition surface
is set as direction in which to change the tilt angles of the
preparation disposition surface, at least two regions in the one
direction are necessary. When both of the X-direction and the
Y-direction as in-plane moving directions of the preparation
disposition surface is set as directions in which to change the
tilt angles of the preparation disposition surface, at least four
regions, that is, two regions in the X-direction and two regions in
the Y-direction, or at least three regions, that is, a region to be
set as a reference, one region at a distance from the reference
region in the X-direction, and one region at a distance from the
reference region in the Y-direction are necessary.
[0136] When parts of the tissue section TS to be obtained as phase
difference images are thus limited, a time to obtain the phase
difference images can be greatly shortened as compared with a case
of obtaining phase difference images of all the parts of the tissue
section TS.
[0137] In addition, in the foregoing embodiment, a straight line
most closely approximating the parallax distribution of each pixel
in the X-Z direction (Y-Z direction) is detected for each column,
and an angle formed between a plane passing through the most of the
straight lines of the respective Y-columns (X-columns) and the
horizontal plane is calculated as a tilt angle of the tissue
section TS. However, a method of calculating the tilt angle of the
tissue section TS is not limited to this.
[0138] For example, in the case of FIG. 12, the X-Z direction tilt
angle of the tissue section TS is approximated by a ratio of a
difference between the X-positions of the regions ARx1 and ARx2 in
the long side direction to a difference between a maximum value and
a minimum value of parallaxes in the regions ARx1 and ARx2.
Therefore, the ratio can be set as the X-Z direction tilt angle of
the tissue section TS. On the other hand, the Y-Z direction tilt
angle of the tissue section TS is approximated by a ratio of a
difference between the y-positions of the regions ARy1 and ARy2 in
the short side direction to a difference between a maximum value
and a minimum value of parallaxes in the regions ARy1 and ARy2.
Therefore, the ratio can be set as the Y-Z direction tilt angle of
the tissue section TS.
[0139] In this case, the number of photographs can be greatly
reduced as compared with a case of photographing the tissue section
TS that remains in a tilted state. In addition to this, because a
processing load can be greatly reduced as compared with a case of
calculating the tilt angles of the tissue section TS using phase
difference images of all parts of the tissue section TS allocated
to the photographing range AR (FIG. 5), thus being able to reduce
the number of photographs greatly is very useful from a viewpoint
of improving efficiency of obtainment of tissue section images.
[0140] As another example, the tilt angles of the tissue section TS
can be calculated by applying a search method employed in
autofocusing. In short, as a method for calculating the tilt angles
of the tissue section TS using parallaxes of all or a part of phase
difference images of the tissue section TS, methods other than the
above illustrated methods can be widely applied as long as the
methods calculate the tilt angles of the tissue section TS
reflecting the depression and projection state (parallaxes) of the
tissue section TS.
[0141] Incidentally, while the tilt angles of the preparation
disposition surface are adjusted so that the tilt angles (the X-Z
direction tilt angle and the Y-Z direction tilt angle) of the
tissue section TS are 0.degree. with respect to the horizontal
plane, this is a case where a state in which the preparation
disposition surface is horizontal is set as a reference, for
example.
[0142] When a state other than the state in which the preparation
disposition surface is horizontal is set as a reference, for
example, an adjusting method is different from that of the
foregoing embodiment. However, it suffices to make adjustment so as
to maintain the number of photographs in the direction of thickness
of the tissue section TS to be photographed at substantially the
same level.
[0143] In short, it suffices to adjust the preparation disposition
surface on the basis of the tilt angles (the X-Z direction tilt
angle and the Y-Z direction tilt angle) of the tissue section TS so
that a tilt within an angle of view of a photographed image is
minimized or so that the preparation disposition surface is
orthogonal to the optical axis LX (FIG. 1) of the objective lens
14.
[0144] In addition, in the foregoing embodiment, the preparation
disposition surface is typically adjusted when there is a tilt
angle with respect to the preparation disposition surface.
[0145] In general, as shown in FIG. 13, an error .DELTA.Z ([mm])
caused by variations in the preparation stage 11, accuracy of
movement, and the like (which error will hereinafter be referred to
as a stage error) is added to an amount of movement Zd ([mm]) of
the preparation stage 11 to be moved in the Z-direction.
[0146] Due to this stage error .DELTA.Z, adjusting the preparation
disposition surface so that a tilt within an angle of view of a
photographed image is minimized may instead invite an adverse
effect of allowing the preparation PRT to strike against the
objective lens 14 or an adverse effect of causing section parts to
exceed the depth of field of the objective lens 14.
[0147] In addition, a distance Zw ([mm]) between the objective lens
14 and the preparation PRT on the optical axis (which distance will
hereinafter be referred to also as a working distance) is shortened
as the magnification (NA) of the objective lens 14 is heightened.
That is, the probability of inviting the above-described adverse
effect is increased as the magnification (NA) of the objective lens
14 is heightened.
[0148] Thus, defining a condition for not adjusting the preparation
disposition surface even when there is a tilt angle with respect to
the horizontal plane is useful from a viewpoint of reducing the
above-described adverse effect.
[0149] Specifically, a threshold value for determining whether to
adjust the preparation disposition surface or not is set for an
amount of extension or contraction (amount of movement in the
Z-direction) of the supporting member 52 or the supporting member
53, which amount of extension or contraction (amount of movement in
the Z-direction) of the supporting member 52 or the supporting
member 53 is calculated by the stage tilt angle adjusting section
65.
[0150] This threshold value is the depth of field of the objective
lens 14. This is because the photographing of the tissue section TS
is not affected substantially when the amount Zd of movement to be
made in the Z-direction is within the range of the depth of
field.
[0151] When the threshold value is set, fifth step SP5 and sixth
step SP6 are changed in the tilt angle adjusting process procedure
shown in FIG. 10 described above. Specifically, the stage driving
control section 31 (stage tilt angle adjusting section 65) in fifth
step SP5 determines an amount of extension or contraction of the
supporting member 53 corresponding to the Y-Z direction tilt angle
calculated in fourth step SP4, and compares the amount of extension
or contraction with the set threshold value.
[0152] When the amount of extension or contraction is smaller than
the threshold value, the stage driving control section 31
determines that the preparation disposition surface is not to be
adjusted, and proceeds to sixth step SP6 without adjusting the tilt
angle in the long side direction (X-direction) of the preparation
disposition surface.
[0153] When the amount of extension or contraction is equal to or
larger than the threshold value, on the other hand, the stage
driving control section 31 adjusts the tilt angle in the long side
direction (X-direction) of the preparation disposition surface
(FIG. 8B) as described above, and proceeds to sixth step SP6.
[0154] In addition, the stage driving control section 31 in sixth
step SP6 determines an amount of extension or contraction of the
supporting member 52 corresponding to the X-Z direction tilt angle
calculated in fourth step SP4, and compares the amount of extension
or contraction with the set threshold value.
[0155] When the amount of extension or contraction is smaller than
the threshold value, the stage driving control section 31
determines that the preparation disposition surface is not to be
adjusted, and proceeds to seventh step SP7 without adjusting the
tilt angle in the short side direction (Y-direction) of the
preparation disposition surface.
[0156] When the amount of extension or contraction is equal to or
larger than the threshold value, on the other hand, the stage
driving control section 31 adjusts the tilt angle in the short side
direction (Y-direction) of the preparation disposition surface
(FIG. 8A) as described above, and proceeds to seventh step SP7.
[0157] Thus, the probability of inviting the above-described
adverse effect is reduced because the photographing of the tissue
section TS is not affected substantially even when no adjustment is
made while there is a tilt angle with respect to the preparation
disposition surface. Incidentally, the probability of inviting the
above-described adverse effect is further reduced when the
threshold value for the amount Zd of movement in the Z-direction
(amount of extension or contraction of the supporting member 52 or
the supporting member 53) is set so as to be lowered as the
magnification of the objective lens 14 is heightened.
[0158] When parts of the tissue section TS to be obtained as phase
difference images are limited as shown in FIG. 12, the range of a
field of view of the phase difference images is reduced as the
magnification of the objective lens 14 is heightened. Thus, as
shown in FIG. 14, a shift width SW by which a field of view FIR of
the objective lens 14 is shifted from the image pickup range AR of
the image pickup element 20 is increased and therefore accuracy of
calculation of the tilt angles tends to be decreased as the
magnification of the objective lens 14 is heightened.
[0159] In addition, as shown in FIG. 13, the smaller the tissue
section TS disposed in the preparation PRT is, the larger a
difference between a tilt angle for a shortest distance L ([mm])
between the central position P.sub.00 of the region ARx1 (or ARy1)
and the central position P.sub.10 of the region ARx2 (or ARy2) and
a tilt angle for the entire width X ([mm]) in the long side
direction (short side direction) of the preparation PRT tends to
be.
[0160] Thus, when parts of the tissue section TS to be obtained as
phase difference images are limited, merely setting a threshold
value for an amount of extension or contraction of the supporting
member 52 or the supporting member 53 which amount of extension or
contraction of the supporting member 52 or the supporting member 53
is calculated by the stage tilt angle adjusting section 65 does not
necessarily reduce the probability of inviting the above-described
adverse effect.
[0161] Therefore, when parts of the tissue section TS to be
obtained as phase difference images are limited, it is useful to
define a condition for preventing the above-described adverse
effect.
[0162] Specifically, letting an allowable amount of shift width SW
(which allowable amount will hereinafter be referred to as a field
of view range allowable amount) be A ([mm]) and a maximum value
assumable as the stage error .DELTA.Z be B ([mm]), the region ARx1
and the region ARx2 (FIG. 12) are determined so as to satisfy the
following expressions:
B/(L.times.X)<Zw
B/(L.times.X)<A (1)
[0163] That is, the region ARx1 and the region ARx2 are determined
by a relation such that the shortest distance L between the central
positions P.sub.00 and P.sub.10 is increased with respect to a
value obtained by dividing the stage error .DELTA.Z by the stage
length (width length in the long side direction or the short side
direction) of the preparation PRT according to the magnification of
the objective lens 14.
[0164] Incidentally, parameters other than "L" in Expression (1)
are for example stored in a storage section 27 or the like.
Incidentally, the working distance Zw and the field of view range
allowable amount A are each stored in the storage section 27 or the
like in association with the magnification of the objective lens
14.
[0165] When the region ARx1 and the region ARx2 are determined by
using Expression (1), a new step to be performed in a stage
preceding first step SP1 is added to the tilt angle adjusting
process procedure shown in FIG. 10 described above.
[0166] Specifically, before preceding to first step SP1, the stage
driving control section 31 (stage tilt angle adjusting section 65)
arbitrarily determines each of the region ARx1 and the region ARx2
and the region ARy1 and the region ARy2 as a candidate.
[0167] The stage driving control section 31 also obtains a distance
L between the central position P.sub.00 of the region ARx1
determined as a candidate and the central position P.sub.10 of the
region ARx2 determined as a candidate and a distance L between the
central position P.sub.00 of the region ARy1 determined as a
candidate and the central position P.sub.10 of the region ARy2
determined as a candidate. In addition, the stage driving control
section 31 obtains parameters other than these distances L from the
storage section 27 or the like. The stage driving control section
31 thereafter substitutes the parameters and the distances L into
Expression (1) and determines whether Expression (1) is
satisfied.
[0168] When Expression (1) is not satisfied, the stage driving
control section 31 determines new candidates again, and substitutes
the distances L between the newly determined regions AR and the
parameters obtained from the storage section 27 or the like into
Expression (1).
[0169] When Expression (1) is satisfied, on the other hand, the
stage driving control section 31 proceeds to first step SP1. In
this case, the stage driving control section 31 scans the
preparation stage 11 so as to assign the region ARx1 and the region
ARx2 and the region ARy1 and the region ARy2 determined as
candidates to the image pickup range AR (FIG. 5). The stage driving
control section 31 then proceeds to second step SP2 to obtain phase
difference images of the region AR.
[0170] Thus defining Expression (1) reduces the probability of
parts of the tissue section TS to be obtained as phase difference
images inviting the above-described adverse effect.
[0171] In addition, in the foregoing embodiment, the two separator
lenses 19A and 19B are used. However, the number of separator
lenses 19 is not limited to the embodiment. A plurality of
separator lenses 19 can be used with a pair of separator lenses 19A
and 19B as a unit (set). Incidentally, in this case, apertures
corresponding to each set of separator lenses 19 need to be
provided in the diaphragm mask 18.
[0172] In the foregoing embodiment, phase difference images are
formed by the separator lenses 19A and 19B. However, a method for
forming phase difference images is not necessarily limited to the
embodiment, but another known method may be adopted.
[0173] In addition, the foregoing embodiment is applied to the
microscope 1. However, the device is also applicable to various
devices having a stage on which a sample is disposed.
[0174] The present embodiment is applicable in the biotechnology
industry for gene testing, creation of medicines, patient follow-up
or the like.
[0175] It should be understood that various changes and
modifications to the presently preferred embodiments described
herein will be apparent to those skilled in the art. Such changes
and modifications can be made without departing from the spirit and
scope of the present subject matter and without diminishing its
intended advantages. It is therefore intended that such changes and
modifications be covered by the appended claims.
* * * * *